"It's with incredible shock and sadness that I'm letting our friends and family know that my amazing brother, Dave Goldberg, beloved husband of Sheryl Sandberg, father of two wonderful children, and son of Paula Goldberg, passed away suddenly last night," he wrote.

Under Dave Goldberg, SurveyMonkey grew from a handful of employees to more than 450 and acquired 25 million customers.

His fortunes was closely linked to those of Silicon Valley - a media company founded by him, Launch Media, was taken over by Yahoo in 2001, just after the "dotcom bubble" burst.